Altered lung biology of healthy never smokers following acute inhalation of E-cigarettes

Introduction:
This text provides an overview of a study examining the effects of electronic cigarette (EC) aerosol exposure on the biology of lung cells in healthy never smokers. The study aims to assess the potential risks associated with EC use, particularly in relation to the widely held belief that EC are safer than traditional cigarettes. The study design includes a small cohort of 10 healthy never smokers who were assessed before and after acute exposure to EC aerosols, with 7 inhaling aerosols from EC with nicotine and 3 inhaling aerosols from identical EC without nicotine.

Key points:

* The study used fiberoptic bronchoscopy to assess the transcriptome of the small airway epithelium (SAE) and alveolar macrophages (AM), and flow cytometry analysis of plasma pulmonary capillary-derived endothelial microparticles (EMP).
* Acute exposure to EC aerosols resulted in altered transcriptomes of SAE and AM for all subjects, regardless of nicotine content.
* Plasma EMP levels were significantly elevated following inhalation of EC with nicotine.
* The SAE and AM of EC users expressed multiple nicotinic acetylcholine receptor (nAChR) subunits.
* The nicotine receptor pathway and several downstream targets of p53 were significantly affected in SAE following exposure to EC with nicotine.
* Several genes known to have roles in macrophage physiology and pulmonary health were affected in AM following exposure to EC.
* There were no consistent changes in vital signs, lung function tests, O2 saturation, blood carboxyhemoglobin levels or urine nicotine metabolite levels, bronchoalveolar lavage cell differentials or small airway epithelium cell differentials following EC exposure.

Main message:
The study provides in vivo evidence that acute exposure to EC aerosols dysregulates normal human lung homeostasis, even in healthy naïve individuals. These observations have implications for new EC users, nonsmokers exposed to secondhand EC aerosols, and cigarette smokers using EC to quit smoking. While the long-term health effects of EC use are still unclear, the study suggests that EC are not benign and that additional research is needed to fully understand their potential risks.

Staudt, Michelle R., Jacqueline Salit, Robert J. Kaner, Charleen Hollmann, and Ronald G. Crystal. “Altered Lung Biology of Healthy Never Smokers Following Acute Inhalation of E-Cigarettes.” Respiratory Research 19, no. 1 (December 2018): 78. https://doi.org/10.1186/s12931-018-0778-z.